【摘要】 雪粒的起动以及临界起动风速是研究风雪流的形成过程中需要关注的首要问题．通过对雪粒的受力机制及其起动条件进行分析,建立了雪粒在平稳风场下的起动模型;研究了雪粒的临界起动风速以及临界起动风速与雪粒粒径、积雪时间和雪表温度的关系．结果表明,临界起动摩阻风速随着雪粒粒径的增大而增大;对于稳定的雪表温度,雪粒的起动摩阻风速在1000 s内是随时间而增加的,最终达到一个稳定值．起动摩阻风速随雪表温度的增大而增大,当雪表温度大于263 K时,其对临界起动摩阻风速影响很大;当雪表温度小于263 K时,其对临界起动摩阻风速影响相对较小．更多还原

【Abstract】 The initiation and threshold wind speed of snow particles are basic to the research of snow drifting. Through analysis of the forces on particles, this paper establishes a model of initiation of snow particles under stable wind speed. Then the relationships among the threshold wind speed and particle size, duration time of snow particle and surface temperature of particles are analyzed. The results show that the threshold wind speed increases with the particle size. For the constant surface temperature the threshold wind speed increases as the duration time of snow particle increases when the duration time is shorter than 1 000 second and finally it will attains a stable value. The results also show that the threshold wind speed increases as the surface temperature increases and the effects of the surface temperature on the threshold wind speed are great when the surface temperature is higher than 263 K and its effects are relatively smaller when the surface temperature is below 263 K.更多还原